In a large saucepan with a lid, heat 2 tablespoons of oil over medium heat. Add the shallots, salt, and pepper, and cook, stirring, until shallots begin to soften, about 3 minutes. Stir in the barley and continue stirring to toast lightly, about 2 minutes. Stir in 3 cups of the broth and the thyme and bring to a boil; reduce the heat to low, cover with the lid and simmer until the barley is tender to the bite and most of the broth is absorbed, about 14 minutes. Remove from the heat and keep covered.

While the barley is cooking, prepare the mushroom and grape mixture: In a deep, large skillet or wide, enameled Dutch oven, heat 1 tablespoon of oil over medium-high heat. Add one-third of the mushrooms, and cook, stirring occasionally, until golden-brown, about 5 minutes. Transfer the cooked mushrooms to a bowl, and repeat with the remaining mushrooms and oil, adding 1 tablespoon more oil per batch. When all the mushrooms are cooked, return them to the skillet and season to taste. Pour in the wine and stir to deglaze the pan. Once the wine has evaporated, add the cooked barley to the skillet with the mushrooms; stir in the remaining broth, parmesan, and grapes. Cook, stirring, until the mixture is piping hot. Season to taste and stir in the chives.

Ladle the risotto into shallow bowls and serve each portion with sprinkle of parmesan cheese.